Bone prostheses with direct cast macrotextured surface regions and method for manufacturing the same

Abstract

An implantable article having on at least a portion of its exterior surface an integral, as-cast macrotextured surface having pores with undercut edge profiles is provided. The integral, as-cast macrotextured surface is able to be formed on the implantable articles by a modified casting process. As part of a casting process, positive models of the articles to be cast, or parts thereof, are formed by stereolithographic techniques. Cavities or molds, representing negative images of the articles to be cast, are then formed by encasing one or more models in a refractory material. The positive models are then extracted by heating and thus melting the material from which they are made. Thereafter, molten casting material can be poured into the resulting mold to obtain the implantable articles.

What is claimed is: 
     
       1. A bone prosthesis comprising an implantable article having an outer bone engaging surface, wherein at least a portion of the outer bone engaging surface has cast thereinto an integral macrotextured surface that includes macropores, wherein at least some macropores have undercut edge profiles, and the macropores have a diameter in the range of about 150 to 600 micrometers. 
     
     
       2. The bone prosthesis of claim 1 having porosity in the range of about 30 to 60%. 
     
     
       3. The bone prosthesis of claim 1 wherein the implantable article is a femoral stem for an artificial hip. 
     
     
       4. The bone prosthesis of claim 1 wherein the implantable article is an acetabular shell component of an artificial hip. 
     
     
       5. The bone prosthesis of claim 1 wherein the implantable article is a tibial plateau of an artificial knee. 
     
     
       6. The bone prosthesis of claim 1 wherein the implantable article is a femoral component of an artificial knee. 
     
     
       7. The bone prosthesis of claim 1 wherein the macropores are shaped as spatial complements of an array of protruding undercut macrofeatures. 
     
     
       8. The bone prosthesis of claim 7 wherein the macrofeatures are selected from among bridges, hooks, ridges and tunnels.